Capture of gases emitted from power plants that include fuel cell generated power is an area of increasing interest. Power plants based on reactions that occur within molten carbonate fuel cells generate carbon dioxide (CO2) as a by-product of the reaction. Historically, CO2 has been either released into the atmosphere after the reaction takes places or prepared for storage by expensive and energy demanding processing prior to the storage. Therefore, traditional disposal of CO2 in the process of power generation has been energy consuming. As a result, it is becoming increasingly desirable to identify alternative ways to process and recycle CO2 generated during the fuel cell reactions.
Moreover, certain types of fuel cell technologies require CO2 as one of the reactants in the process of power generation. At the same time, the emission gases that include CO2 normally do not produce separated and isolated CO2 ready to be used in a chemical reaction required to generate power. This poses an additional challenge where, while recycling CO2 into molten carbonate fuel cells as a reactant could decrease the need for storing it, the process of separating CO2 out of the emission mixture to be usable as a reactant draws a significant amount of energy. Thus, a need arises to develop new ways to inexpensively and efficiently prepare CO2 to be fed back into the power generation process as a reactant.
Further, in molten carbonate fuel cells, hydrogen (H2), the fuel gas, often does not react entirely, but is released as an emission gas. In order to maximize utilization of H2 in the power plant, unreacted H2 would need to be purified and fed back into the fuel cells.
One of the common problems of the task of preparing CO2 for storage and the task of separating the reactant gases in order to convert them into suitable reactants is that, because they are portions of the emission mixture, they are available at high temperatures. Further, in instances where this preparation and separation is performed by pressure swing adsorption (PSA), for example, the emission gas at the outlet of a molten carbonate fuel cell flows at a relatively low pressure (˜1 bara). Thus, in view of the commonality of these processes, which are typically integrated in a single power generation system, there is a need for a solution that would address the discussed problems while minimizing the footprint of the system and while increasing its energy efficiency.